| .TH IM_QUANTIM 3 "10 May 1991" |
| .SH NAME |
| im_quantim, im_quantlut, im_spatres \- quantise an image or a lut |
| .SH SYNOPSIS |
| .B #include <vips/vips.h> |
| |
| .B int im_quantim(in, out, no_of_bits) |
| .br |
| .B IMAGE *in, *out; |
| .br |
| .B int no_of_bits; |
| |
| .B int im_quantlut(lut, no_of_bits) |
| .br |
| .B IMAGE *lut; |
| .br |
| .B int no_of_bits; |
| |
| .B int im_spatres(in, out, step) |
| .br |
| .B IMAGE *in, *out; |
| .br |
| .B int step; |
| .SH DESCRIPTION |
| .B im_quantim() |
| quantises the image file held by in using no_of_bits and writes the result to |
| out. The no_of_bits should be between 1 and 7 inclusive. Input can have any |
| number of bands. The function expects as input a valid unsigned char image. |
| |
| These functions are here for compatibility only. You should use the boolean |
| operations im_andconst(3), im_orconst(3), im_shrink(3), im_zoom(3) and |
| im_lowpass(3). |
| |
| .B im_quantlut() |
| creates an one band unsigned char |
| lookup table which is used by im_quantim(3). |
| The no_of_bits should be between 1 and 7 inclusive. |
| |
| .B im_spatres() |
| reduces the spatial resolution of in by averaging step*step pixels |
| and replicating the result in out. The function can be used in |
| order to show the effect of reducing the spatial resolution of a given image |
| and the importance of post-filtering before displaying. |
| Input can have any number of bands. |
| .SH RETURN VALUE |
| All functions returns 0 on success and -1 on error. |
| .SH SEE ALSO |
| im_andconst(3), im_orconst(3), im_shrink(3), im_zoom(3) im_lowpass(3). |
| .SH COPYRIGHT |
| .br |
| N. Dessipris |
| .SH AUTHOR |
| N. Dessipris \- 10/05/1991 |
